there is the united states of america. there is not a black america and a white america and latino america, an asian america, but there is the united states of america. >> from the first time he took to the convention speech as the keynoter in 2004, there has been no doubt that barack obama can step into the spotlight and dazzle. four years later in denver the optics match the excitement for the presidential campaign with greek columns surrounding him in front of a crowd of more than 75,000. the democratic nominee delivered an electrifying speech. >> out of work, tough luck, you are on your own. no health care? the market will fix it. you're on your own. born into poverty? pull yourself up by your own boot straps, even if you don't have boots, you are on your own. [ cheers and applause ] >> well, it is time for them to own their failure. it is time for us to change america, and that's why i'm running for president of the united states. >> this week in tampa republicans argue that barack obama is a great talker who doesn't